Crossing Vulnerability Strike / 半渡击敌

Definition

Crossing Vulnerability Strike / 半渡击敌 is the tactic of attacking an enemy while its force is divided, disordered, or command-limited during a river crossing, before the whole army has completed the passage and reformed for battle.

Current Synthesis

The current synthesis is source-scoped to Hanji 1057’s Pingyang branch. It differs from 渡河欺敌 because the key actor is not hiding his own crossing route; instead, the defender waits for the opponent’s crossing process to create a temporary vulnerability. In the episode, Zhang Ji’s advice to 钟繇 turns 郭元’s incomplete Fen River crossing into the decisive moment.

Key Claims

• A crossing force is temporarily weaker because part of it is across, part remains behind, and formation/command continuity is disrupted.
• The tactic depends on timing more than attrition: the attack must land before the enemy finishes crossing and reorganizes.
• The crossing window is most exploitable when the enemy commander is proud, careless, or insufficiently alert to local defenders.
• The tactic can be the battlefield payoff of prior diplomacy if an opponent’s supporting alliance has already been weakened.

Evidence

• Crossing-state vulnerability: Hanji 1057 records Zhang Ji urging Zhong Yao to attack Guo Yuan because the enemy has not fully crossed the Fen River.
• Commander-temperament timing: Hanji 1057 says Zhong Yao refuses withdrawal from Pingyang because Guo Yuan is proud and not careful enough.
• Diplomacy-to-battle sequence: Hanji 1057 frames the battle after Zhong Yao first reassures Ma Teng, limiting the Yuan-family plan to combine Guo Yuan, Ma Teng, and the Southern Xiongnu.

Counterevidence & Qualifications

This concept currently rests on one source note and should stay narrow. It should not absorb all river tactics: hidden-route deception belongs under 渡河欺敌, while retreat-bait pursuit traps belong under 诱敌离位. The present concept requires an enemy crossing in progress and an attack timed against that transitional state.

What Changed

• Created the concept from Hanji 1057’s Pingyang/Fen River timing window.

Related Concepts

• 渡河欺敌 - neighboring river-tactic concept focused on deceiving the enemy about one’s own crossing route.
• 诱敌离位 - broader position-control family, related when an enemy moves into a vulnerable operating condition.
• 战场信息控制 - perception and timing discipline that help identify when the crossing window is real.
• 战争成本与速决纪律 - tempo concept connected to converting a brief vulnerability into decisive action.
• 行势情战略评估 - strategic-assessment frame for reading alliance conditions before the battlefield moment.